遙測應用於藤枝地區之森林干擾度偵測

Remote Sensing for Use in Forest Disturbance Detection in Tengjhih Area of Taiwan

當今全球氣候異常的趨勢下，研究有關森林干擾度偵測的方法，可瞭解森林在不同時間與空間受干擾的程度，有助於經營管理策略的施行。本研究目標係挑選位於藤枝地區之特有生物研究保育中心所轄中海拔試驗站及其周邊範圍作為研究區，廸立一以遙測為基礎的偵測指標，用於評估森林受干擾的程度。首先蒐集受天然災害影響之前期及後期（2009與2013年）Landsat影像，利用混合式分類法與變遷分析等影像處理技術，瞭解研究區土地覆蓋變遷之情形，再利用常態化差異土壤指標（normalized difference soil index）、植生指標（normalized difference vegetation index）及水指標（normalized difference water index）等3種光譜反射指標的組合運算，獲取干擾度指標（disturbance index, DI）。研究結果顯示，本研究所建構之DI可有效地偵測森林受干擾的程度，另一方面，未來亦可作為自然保育策略執行成效之監測工具。

The detection of forest disturbance is important in research under global climate anomaly. It is also useful for identifying spatial and temporal trends in forest management. Our goal here was to create a remote-sensing-based index in order to assess forest disturbances in medium altitude experimental station of Endemic Species Research Institute and surroundings with in Tengjhih area. First, we applied Lands at images before and after natural disaster (2009 and 2013) with a hybrid classification and change analysis to understand land-cover changes within the study area. Second, the disturbance index (DI) was tested, which was a novel combination of the three spectral reflectance indices, normalized difference soil index, vegetation index and water index. Results revealed that the DI not only can efficiently detect forest disturbances but also provide an important tool for monitoring the success and failure of conservation efforts in the future.